Mining machine



C. E. DAVIS MINING MACHINE June 24, 1930.

Filed Feb. 3, 192'? 5 Sheets-Sheet f Za Julie 24, 1930. I C, E, DAVlS 19765570 MINING MACHINE Filed Feb.A 3, 1927 5 Sheets-Sheet 2 IW l C. E. DAVIS MINING MACHINE June 24, 1930.

5 Sheets-Sheet 5 June 24, 1930. c, E DAVIS 1,765,570

MINING MACHINE Filed Feb. 3, 1927 5 Sheets-Sheet 4 be/22W afZQ/S E Wim# a MLK June 24, 1930. Q E, DAvls 1,765,570

MINING MACHINE Filed Feb. 5, 1927 5 Sheets-*Sheet 5 7 @fa/75W Patented June 24, 1930 l UNITED STATES PATENT OFFICE CHARLES E. DAVIS, OF DAVENPORT, FLORIDA, ASSIGNOR TO GOODMAN MANUFACTUR- ING COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS MINING MAcHiNE Application filed February 3, 1927. Serial No. 165,63951 This invention relates to improvements in mining machines and relates more particularly to the type of self-propelled vehicle adaptable for use in coal mines to transport coal cutting machines and its accessories including a power cable, about a coal mine on the rails, and beyond the rails wherey it is impractical or uneconomical to lay rails. It may be understood that although my invention relates primarily to mining machines, its use is not restricted to mining machines or use in mines and that it may be used to transport other equipment under other conditions.

The principal object of my invention is to provide an improved type of self-propelled vehicle adaptable to transport a mining machine on rails or on the mine bottom, with a novel and improved means to steer said vel" hicle while operating on the mine bottom,

and to include an improved automatic device.

for carrying and reeling or unreeling an electric power cable for said mining machine.

A prior Patent No. 1,548,664, issued to me August 4, 1925, relates to an apparatus of the class herein described, adapted to be operable on mine rails or on a mine bottom. My present invention improves over the apparatus in this prior patent in that I use a new and novel traction means for driving my truck on the ground providing an additional geared reduction, operative when my truck is travelling on a mine bottom, but inoperative whentravelling on the rails, with a novelmeans for steering my truck, and a means whereby an improved cable reel is provided as a unit with my truck. My traction driving meansV also comprises a novel means for causing my device to be operable on a mine bottom and inoperable on mine rails. The additional geared reduction'used while operating my device on a mine bottom enables my truck to more Veasily traverse a rough or soft mine bottom than could be travelled with other devices used for the same purpose, since travelling on rough ground necessarily requires more power, than would be needed while operating on the rails. The incorporation of a cable reel as a unit of my device eliminates the pulling of a cable reel after the device.

My invention may be best understood by reference to the accompanying drawings wherein:

Figure 1 is a side elevation of the devicev embodied in my invention with a mining machine thereon in position to move about on the rails;

Figure 2 is-'a plan view of the device embodying my invention;

Figure 3 is a fragmentary sectional view taken on line 3 3 of Figure 2, showing the details of the forward flanged driving wheel and the tractionscwheel;

Figure 4 is a fragmentary end elevation of the flanged and tractor` driving wheels; Figure 5 is an enlarged fragmentary plan view of the rearward portion ofthe view shown in Figure 2; and

Figure` 6 is an enlarged fragmentary sectional view taken on line 6 6 of Figure 5.

In the embodiment of my present invention, as illustrated in the drawings, a mining machine truck indicated at 1 is provided with ,a body portion 2 for carrying a load which in this case comprises a minin machiney 3. In the preferred form herein, t e body portion 2 is provided with a pair of forward axles,44, which are supported'in said body portion and brackets 5 5 on each side thereof. Flanged Wheels 16-16 are loosely mounted on the axles 4 4 and are driven by sprockets 17e- 17 on said axles. Traction wheels 18-18 are also eccentrically mounted on the axles 4 4, as for instance, on the. outside of the sprockets 17-17 and aredriven by said sprockets byl a suitable geared reduction and are furthermore adaptable to be engaged br disengaged with the ground. The construction of these traction wheels with the drive, an'd method of engaging or disengagling said wheelswith the ground is one of the novel features gf my invention and will hereinafter be more fully 'explained The rear of the body portion 2 is supported v by a supporting frame 19, having axles 2A0 20 with supporting wheels 21-21 thereon. This vides a means for supporting an electric .cable reel 22, as will hereinafter more fully appear.

Referring now to the details of construction of the forward driving wheels (Figures 3 and 4) it will be seen that the anged wheel 16 is loosely mounted on the axle 4 and nas driving connection with the sprocket 17 through teeth 23 projecting from the side of the Wheel 16 and meshing with jaws 24 in the hubr of the sprocket 17. The sprocket 17 also has teeth 25 on its outer side which fit in jaws 26 vin the hub of a pinion 27 to cause rotation of said pinion. The flanged wheel 16 also has auxiliary jaws 28 on its inner hub. These jaws permit the sprocket and wheel to be transposed so that two different track gauges may be had without necessitating the design of new parts. by interchanging the position of the sprocket 17 with the wheel 16 so the teeth 23 on the sprocket 17 mesh with the jaws 28 on the inner side of the wheel hub, and the teeth 23 on the outer side of the wheel hub mesh with the jaws 26 on the pinion 27.

In Figures 3 and 4 I have shown in detail the traction wheel 18 and it may be seen from these figures that said wheel is comprised of a circular disk 29 eccentrically mounted on a suitable bearing 31 onthe hub of the pinion 27 and another circular disc 30 eccentricall mounted on a suitable bearing 32 on theshafiI 4. Suitable bearings 37 and 38 surround the circular discs 29 and 30,*respectively. A cylinder 39, having a traction tread 4() on its outer periphery and a bearing surface 41 on each end of its inner periphery with an internal spur gear 42 between said bearing surfaces, lits and rotates on the bearings 37 and 38 on the discs 29 and 30. The spur gear 42 meshes with the pinion 27; A sector 44 is integral with the disc 30 and projects outwardly therefrom. Notches 45 and 46 are provided in said sector and are adapted to be engaged by a pivotally mounted locking arm 47 which when engaged in either the notches 45 or 46 holds the disc 30 -from rotation. A spacer 48 serves to space the discs 29 and 30 at the proper distance and to hold the disc 29 stationary when the disc 30 is held sta-y tionary. Studs 49 pass through said discs and spacerr and hold said discs together by means of suitable nuts threaded thereon:

Y 47 and start thev truck in a forward direction with said locking levers released until said :tact with the lever 47. is very seldom used however, as in most causes .the truck is brought to a point near the end This is accomplished locking levers can be placed in the notches 45. Additional holes 50 are provided in the sector 44 for the insertion of a bar or jacking means to aidin bringing the notch 45 in con This auxiliary means of the rails where the vertical height from Vthe rail to the ground is enough so that the wheel 18 may be swung down to its driving position by hand.l The Vtruck isthen run olil 'the end of the rails onto the ground. It may thus be seen that means are provided whereby my device may be operable on a mine track -at a certain speed or on a mine bottom at another slower speed obtained through the geared reduction from the pinbion 27 to the. gear 42, and therefore l as the necessary power to traverse obstrutlions and the rough mine bottoms which may be encountered.

Referring now to the driving mechanism, power for opera-ting the truck may be derived from any suitable source such as a motor carried b v the truck. In the embodiment illustrated I have shown an arrangement whereby the motor of a mining machine may be utilized for this purpose. This arrangement comprises a rotatable coupling link 54 which is adapted to be connected'with a suitable motor driven shaft on a mining machine 3 when the mining machine is loaded in place on the truck as shown in Figure 1. Said coupling link is operatively connected with a spur gear having a sleeve 56 integral therewith. Said sleeve is journaled in a support 57 mounted on the `body of the rear frame 19.

The driving connections from the gear 55 to each of the sprockets 17-17 are similar in construction with the exception of the drive lfor the cable reel and a few minor details,

so the description of one driving connection Ywill serve for both, except in the above men tioned cases. which will be described in their order. Me'shing with the gear 55 in Figure 5, is a spur gear 58 having a hub 59 integral therewith. The hub 59 is journaled in suitable bearing supports 60. Said gear 58 is keyed to a shaft 61 which extends forward to a suitable bearing in the frame 19 and extends rearward as a drive for the cable reel 22. It may 'also be seen that the gear 58 on the left hand side of the truck has a hub 59 integral therewith journaled in a suitable bearing sup- -shaft 61 only will hereinafter be mentioned.

A planetary reduction gearing with a frictional control is provided in the driving connection to the sprockets 17-17. This frictionally controlled planetary reduction gearing is of the type commonly used on mining machines and trucks, and includes a drum 65 loosely mounted on the shaft'61, forward of the gear 58 and having a friction band 66 thereon. This friction 'band is controlled by a means which will hereinafter be described, so that pressure on the drum 65 through the band 66 will cause rotation of a bevel gear 67 keyed to a hub 68 of a cage 69 which in turn carries suitable planetaryI pinions 70 in thel well known manner of gear reduction mechanisms of this type. The bevel gear 67 drives a bevel gear 74 keyed to a shaft 75 and journaled on its hub is a suitable bearing bracket 76 on the supporting frame 19. A spur gear 77 is keyed to the shaft 75 and rotates an idler gear 78. It will be noted that bevel gear 74 meshing with bevel gear 67 on the lleft hand side of my device is not journaled in the machine frame but has a spur gear 77 keyed to its hub. This bevel gear-is keyed to a shaft 75a which is supported in a suitable bearing 'journal (not shown) to support the, bevel gear 74. The above mentioned construction is necessary to cause the sprockets 17-17 to rotate in the same direction. Rotation of the idler gear 78 rotates a spur gear 79 keyed to a shaft 80. A sprocket 81 is keyed to said shaft. A driving chain 82 connects the sprocket 80 with the sprocket 17 and rotates said sprocket. Rotation ofv the sprockets 17-17 rotate the wheels 16--16 and 18-18 adaptable to drive the truck either on thev rails or ground as desired.

Referring now more particularly to the v details of the steering device as shown in Figures 2, 5 and 6, it may be seen that forks 85 are provided for supporting the wheels 21 and axles 20 and thaty said forks are pivotally mounted in the supporting frame 19 by pivot pins 87. These pins each have a crank leverI 88 fixed to the upper portion thereof. A rack 89 is mounted transversely of the truck frame 19 and-is slidable in said. frame. Two

,cams 90, 90, are integral with the rearward portionof the rack 89 and are on each side of the center of said rack. These cams are of the same construction but one cam is on the lower side of the rack 89 and the other -cam is on the upper side of said ,rack at the the truck vframe 19. Connecting levers 94, 94, connect the rack 89 with the crank levers 88, 88. Rotation of the hand Wheel 93 therefore causes l pivotal movement of the forks 85, 85, and thus turns the wheels 21, 21. Rollers 95', 95, are mounted on bell crank levers 96, 96, and ride on the cams 90, 90. vOne roller is mounted on the upper side of one bell crank lever while the other roller is mounted on the under side of the other bell crank lever so one roller may engage th upper c am 90 on the rack 89 and the other roller may engage the lower cam 90 on the rack 89 on ,the opposite end thereof. The bell crank levers 96, 96, are pivoted on the o posite sides of the supporting frame 19 at 9 97. One lever arm 98 bears against lugs 99on one end of the friction band 66. The other end of said friction band is fixed to the supporting frame 19 by an arm 100 having an adjusting screw 101 extending therethrough and bearing against a lug 102. Therefore, when the lever arm 98 bears on the lug 99 and forces the ends of the friction band 66 together, the friction drum 65 is held from rotation and power is applied to the driving wheels. When the roller- 95 is on the depressed portion of the cam 90, the ends of the friction band 66 are allowed to separate. This allows the friction drum 65 to rotate and cause power to be released from the driving wheel driven by that friction drum. When operating Aon the rails or on the ground in a straight line the rollers 95, 95, will be on the raised portion of the cams 90 and both wheels will be driven at a constant speed. When operating on the ground and it is desired to turn the truck, it is only necessary to turn the hand wheel 93 according to the direction in which it is desired to turn the truck. This will cause the rack 89 to move transverse to the frame 19 which causes the wheels 21 to be turned on their vertical axes. At thesame 'time one roller 95 will ride on the cam 90 while the other roller 95 will ride on the depressed portion of said ca m Whichwill cause vpower to be applied to one traction wheel land released from the other traction wheel.

This quickly turns the truck about one of the forward wheels (depending upon which way the truck is to be turned) as a pivot point, with the additional aid of the yrearward wheels- This construction enables my mining machine truck to negotiate the mine bottom and turn sharp curves and more easily pass through narrow'breakthroughsI or passageways.

The cable reel 22 is supported on the truck 1 to the rear of the power frame 19 by suitable brackets 103 and 104 and has connection with the driving mechanism for propelling said truck by the shaft 61 whichhas a helical gear 105 loosely, mounted near the outer end. A suitable clutch which in this case'is a jaw clutch 106 operatively connects the gear 105 with the shaft 61. The gear 105 has driving connection with another helical gear 107 keyed to a sleeve 108 loosely mounted on a horizontal shaft 109 extending transversely to the frame 19. A means is provided whereby. power to the cable reel 22 may be automatically released to prevent damage to the cable in case said cable should accidentally get caught or fouled while being wound in. A friction means is provided to automatically release power from said cable in this case, and comprises a friction disc 110 having operative connection with the sleeve 108 through jaws 111 and teeth 112. Another friction disc 113 abuts the disc 110 and has operative connection with a reel 114. Pressure of the disc 110 against the disc 113 causes rotation of the disc 113 by the disc 110 and thus drives the reel 114.v The amount of pressure applied by the disc 110 determines the point at which the disc 113 will slip and thus determines the point at which power willv cease to be transmitted tothe reel 114. A spring 115 fits on the shaft 109 and bears against a collar 116 on the sleeve 108 at one endand a collar 117 at the other end. The tension of said spring is adjusted by a nut 118 and the tension ofy said spring therefore determines the amount of power applied to the reel 114 and the point at which the reel will unwind in case the cable gets caught while winding in.

In the embodiment of my invention as has been described it has been seen that a mining machine truck is vprovided with forward tractor driving wheels in addition to the usual flanged wheels so that my truck may be operated over a track in the usual manner, but when it is desired to transport the mining machine beyond the track, the tractor wheels may be lowered to support the forward portion of thetruck and drive the truck and machine over the ground or .mine bottom. It has been seen that a novel means has been provided for steering my device on the mine bottom whereby my device will quickly and sharply turn with the aid of all four wheels and that a cable is carried to supply .power to my device when traversing beyond the source of power. The rearward portion of my device is supported on the usual flanged track wheels which in this case are large enough to supportl the weight of the rearward portion of the machine and truck on the ground.

It is advantageous to have a truck such as has here been described in my invention since there are man instances where it is not 'deemed advisa le or leconomical to extend to the nface of the coal by its draft ropes.

This is a hard process and takes valuable time which is not necessary wheny such a truck as has been described as my invention is used. My device is especially adaptable to conditions where the coal is loaded to cars. on the entry by conveyors or scraper loaders since no tracks are laid to the face of the coal under such conditions and the room neck is often blocked up by the loading apparatus so that it is necessary to transport the machine to the working face through adjoining rooms and breakthroughs.

While I have shown and ldescribed one form in which my invention 'may be embodied, it will be understood that the construction and arrangement of the various parts may be altered without departing fromthe spirit and scope thereof. Moreover I do not wish to be construed as limiting myself to the identical or particular construction illustrated, excepting as it may be specifically limited in the appended claims. I claim as my invention:

1. In combination with a mining machine, a truck, supporting wheels and axles therefor, driving means for a pair of track wheels of said truck, auxiliary traction driving wheels eccentrically mounted on said pair of track wheel axles, and means whereby said truck may be supported and propelled on either said track wheels or said traction wheels.

2. In combination with a mining machine,y a truck, supporting track wheels and axles therefor, driving means for a pair of track wheels of said truck, auxiliary traction driving wheels eccentrically mounted on said `track wheel axles, a single driving means for said traction driving wheels and-said track wheels, and means whereby said truck may be supported and propelled on either said track wheels or said traction wheels. A

3. In combination with a mining machine, a truck, supporting track wheels and axles therefor, driving sprockets connectablewith a pair'of track wheels of said truck, means to drive said sprockets, auxiliary traction driving wheels eccentrically mounted on said track wheel axles, and a geared reduction whereby said traction driving wheels may be driven from said sprocket at a slower speed than said track wheels.

4. In combination with a mining machine, a truck, supporting track wheels and axles therefor, driving sprockets connectable with a pair of track wheels of said truck, means to drive said sprockets, auxiliary traction driving wheels eccentrically. mounted on said track wheel axles on the outside-thereof, and a geared reduction whereby said traction driving wheels may be driven at a slower speed than said vtrack wheels from said Y sprocket comprising a pinion `coaxial 'and connectable with said sprocket, 'and an internal gear driven bysaid pinion and integral wlth said traction wheels.

5. In combination with a mining machine, a truck, supporting track wheels and axles therefor, driving sprockets connectable with the' track wheels of said truck, means to drive said sprockets, auxiliary traction driving wheels' eccentrically mounted on said axles adjacent said track wheels, and comprising a cylinder rotatable on a plurality of circular discs mounted eccentric of said axles coaxial with said track wheels and-having a traction tread on the outer periphery thereof, and an internal gear on said cylinder intermediate said discs, said internal gear meshing with and being driven by a pinion coaxial with said track wheels and connectable with said sprockets. l

6. In combination with a mining machine, a truck, supporting track wheels, and axles therefor, driving sprockets connectable with )the track wheels of said truck, means to drive said sprockets, auxiliary traction driving wheels eccentrically mounted on said axles adjacent said track wheels and comprising a cylinder rotatable on a plurality of circular discs mounted eccentric of said forward axles coaxial withsaid track wheels and havninga 4'traction tread on the-outer periphery thereof, an internal gear on said cylinder intermediate said discs, said internal gear meshing with and being driven by a pinion coaxial with said track wheels and connectable with said sprockets, and a'locking lmeans to prevent rotation of said eccentrically mounted discs. s

7. In combination with a mining machine, a truck, supporting track wheels and axles therefor, driving sprockets connectable with the track Wheels of said truck, means to drive said sprockets, auxiliary traction ldriving wheels eccentrically vmounted* on said axles adjacent said track wheels and comprising a cylinder rotatable on a plurality of circular discs mounted eccentric of said forward axles coaxial with said track Wheels and having a traction tread on the outer periphery thereof, an internal gear on said cylinder intermediate said discs, said internal gear meshing with and being driven by a pinion coaxial with said track wheels and connectable with said sprockets, and a locking means to prevent rotation of said eccentrically mounted discs and hold said' traction Wheels in disengagement with the ground while said track wheels are in yengagement with a rail. f

' 8. In combination with a mining machine,d a truck, supporting track wheels and axles therefor, driving sprockets connectable `withA the track wheels of said truck, means to drive said sprockets, auxiliary traction driving wheels eccentrically mounted on said forward axles adjacent said track wheels and comprising a cylinder rotatable on a plurality` of circular discs 1mounted eccentric of said forward axles coaxial with said track wheels riphery thereof, an internal gear on said cylinder intermediate said discs, said internal gear meshing with and being driven by a pinion coaxial with said track wheels and connectable with sai sprockets, and a locking means to prevent rotation of said eccentrically mounted discs, and hold said traction wheels iniengagernent with the ground and disengage said track wheels with the ground.

9. In combination with a mining machine, a truck, supporting track Wheels and axles therefor, driving sprockets connectable with the track wheels of said truck, means to drive said sprockets, auxiliary traction driving wheels eccentrically mounted on said forward axles adjacent said track wheels and comprising a cylinder rotatable on a plurality of circular discs mounted eccentric of said-forward axles coaxial with said track wheels and having a traction tread on the outer periphery thereof, an internal gear on said cylinder intermediate said discs, saidl internal gear meshing with and being driven by a pinion coaxial with said track wheels and connectable with said sprockets, and locking means to preventrotation of said eccentrically mounted discs, and .hold said traction members in engagement or disengagement with the ground.

10. In combination with a mining machine, a truck, supporting track wheels and axles therefor, driving means for a pair of track wheels of said truck, a vertical pivot mounting for another pair of track wheels and axles, traction driving wheels eccentrically mounted with the firstmentioned pair of wheel axles, and means for driving said traction wheels at a speed slower than said track wheels.

11. In combination with a mining machine, a truck, supporting track wheels and axles therefor, driving means for forward track Wheels of said-truck, a vertical pivotal mounting for rearward track wheels and axles for said truck, means to control the pivotal movement of said rearward track wheels, traction driving wheels eccentrically mbunted with said forward track wheel axles, and a variable friction controlled speed means for d riving said forward traction wheels.

12. In combination with a mining machine, a truck, supporting track wheels and axles therefor, driving meansfor a pair of track wheels of said truck, a vertical plvotal mounting for another pair of track wheels and axles of said-truck, and means to turn said track wheels on their pivot, auxiliary'traction driving wheels eccentrically mounted with said first named track wheels, means tol drivesaidg traction wheels and friction controlled means tov lessen the speed of one traction wheel whilel th'e speed of-said` other traction wheel Y is constant.

13. In combinatlon with a mining machine,

and having a tractiontread on the outer pea truck, supporting track wheels and axles therefor, driving means for a pair of track wheels of said truck, a vertical pivotal mounting for another pair of track wheels and axles of said truck, means to turn said track wheels on their pivot, auxiliary traction driving wheels eccentrically mounted with said track wheels, means to drive said traction 'wheels' and friction controlled means to lessen the speed of one traction wheel while the speed of said other traction wheel is constant, simultaneously as said track wheels are pivoted on their vertical axes.

14. In combination with a mining machine, a truck, supporting track wheels and axles therefor, driving means for a pair of track wheels of said truck, a vertical pivotal mounting for another pair of track wheels and axles of said truck, means to turn said track wheels on their pivot, auxiliary traction driving wheels eccentrically mounted with said driven track wheels, means to drive said traction wheels and friction controlled means to lessen the speed of one traction wheel while the speed of said other traction wheel is constant, simultaneously as said other track wheels are pivoted on their vertical axes, and

means whereby said truck may be propelled on either said track wheels or said traction wheels, rendering the wheels not propelling said truck inoperative.

15. In combination with a mining machine, a truck, supporting track wheels and axles therefor, driving means fora pair ofA track wheels of said truck, a vertical pivotal mounting for another pair of track wheels and axles of said truck, means to turn said track wheels on their pivot, auxiliary traction driving wheels eccentrically mounted with said track wheels, and a friction controlled planetary geared reduction means to drive said traction wheels and to lessen the speed ofv one traction wheel while the speed of saidother traction wheel is constant at the same time said other wheels and axles are pivoted on their vertical axes.

16. In combination with a mining machine, a truck operable on mine rails or a mine bottom, supporting track wheels and axlestherefor comprising a pair of supporting track wheels and a pair of supporting driving wheels, auxiliary supporting traction driving wheels therefor, means to render said traction driving wheels operative and said track driving wheels inoperative'and viceversa, a steering means for said truck comprising a vertical pivotal mounting for said supporting track wheels, means to pivot said track wheels, and drive means for said auxil- `liary traction driving wheels whereby the power to one traction wheel may be lessened while the power'to said other traction wheel remains constant, connected to and operable by said pivoting means for said rearward track wheels.

17. In combination with a mining machine,

a truck operable on mine tracks or a mine bottom, supporting wheels and axles therefor comprising a pair of vertically pivotally mounted guiding track wheels. a pair of driving` track wheels forward of said guiding track wheels, an auxiliary pair of traction driving wheels supported on said track driving wheel axles, a common drive sprocket on each side of said truck to simultaneously drive said tractor and said track drivin wheels,

means to drive said drive sprockets om said mining machine comprising a system of reduction gearing connectable with said mining machine and said sprockets and having a frictionally controlled planetary reduction gearing therein for each of said sprockets, a means whereby either said track driving wheels or said tractor driving wheels may be rendered inoperative and non-supporting while one pair of said driving wheels is operative, a steering means for said truck operable while traversing a mine bottom comprising a means to turn said pivotally mounted rearward track wheels and simultaneously relieve power from said forward traction wheelv 011 which said truck is to turn as an axis, comprising a means operable with said turning device to relieve pressure on one planetary frictionally controlled gearing system and apply the pressure on said opposite planetary frictionally.controlled gear- Aing system, and a frictionally controlled cable reel to the rear of' said truck yand driven by said driving mechanism for said truck.

18. In combination with a mining machine, a truck operable on mine rails or a mine bottom, supporting track wheels and axles therefor comprising rearward supporting track wheels and forward supporting driving track wheels, means to drive said track wheels, auxiliary supporting forward traction driving wheels therefor, means to render said traction driving wheels operative and said track driving wheels inoperative and vice-versaa steering means for said truck, operable whlle said truck is traversing a mine bottom comprising vertically pivotally mounted track wheels, means to control the pivotal movement of said track wheels, and a friction controlled means to drive said auxiliary forward traction driving wheels whereby the power to -one traction wheel may belessened while the power to said other traction driving wheel remains constant, operable by said pivoting control means for said rearward track wheels.

19. In combination with a mining machine, a truck operable on mine rails or a mine bottom, supporting track wheels and axles therefor comprising rearward supporting track wheels and forward supporting driving track wheels, means to drive said track wheels, auxiliary supporting forward traction driving wheels therefor, means to render said traction driving wheels operative and said track driving wheels inoperative and vice-versa, a steering means for said truck, operable while said truck is traversing a mine bottom comprisinga vertically pivotally mounted track wheels, means to control the pivotal movement of said track wheels, and a friction controlled planetary geared driving means for said auxiliary forward traction driving wheels whereby the power to one traction wheel may be lessened while the power to said other traction driving wheel remains constant, operable and controlled by said turning means for said rearward track wheels.

20. In combination with a mining machine, a truck operable on mine rails or a mine bottom, supporting track wheels and axles therefor comprising rearward supporting track wheels and forward supporting driving track wheels, means to drive said track wheels, auxiliary supporting forward traction driving wheels therefor, means to render said traction driving wheels inoperative and said track driving wheels inoperative and viceversa, a steering means f or said truck, operable while said truck is traversing a mine bottom comprising vertically pivotally mounted track wheels, means to control the pivotal movement of said track wheels, and a friction controlled planetary geared driving means for said auxiliary forward traction driving wheels whereby the power to one traction wheel may be lessened while the powerto said other traction driving wheel remains constant, simultaneously as said rearward wheels are turned on their vertical piv- .otal axes.

21. In combination with a mining machine, a truck operable on mine rails or a mine bottom, supporting track wheels and axles therefor comprising rearward supporting track wheels and forward supporting driving track wheels, means to drive said track wheels, auxiliary supporting forward traction driving wheels therefor, means to render said traction driving wheels inoperative and said track driving wheels inoperative and viceversa, a steering means for said truck, operable while said truck is traversing a mine bottom comprising vertically pivotally mounted track wheels, means to control the pivotal movement of said track wheels, and a friction controlled planetary geared driving means for said auxiliary forward traction driving wheels whereby the power to one traction wheel may be lessened while the power to said other traction driving wheel remains constant, simultaneously as said rearward wheels are turned on their vertical pivotal oints and controlled and operated by sai turning means for said rearward track wheels,

on said track driving wheel axles, and a common driving means for said traction and said track driving wheels comprising a motor connectable therewith by means of gearing including a frictionally controlled planetary gear device.

23. In combination with a mining machine, a truck, supporting wheels and axles therefor comprising a pair of guiding track wheels, a pair of driving track wheels and an auxiliary pair of traction driving wheels supported on said track driving wheel axles, and a common drive sprocket on each side of said truck to simultaneously drive said traction and said track driving wheels, a means to drive said sprocket comprising a motor connectable therewith through drive chains and a gearing including a frictionally controlled planetary gear device for each of said drive sprockets. i

24. In combination with a mining machine, a truck, supporting wheels and axles therefor comprising a pair of guiding track wheels, a pair of driving track wheels and an auxiliary pair of traction driving wheels supported on said track driving wheel axles, and a common drive sprocket on each side of said truck to simultaneously drive said traction and said track driving wheels, a means to drive said sprocket comprising a motor connectable therewith through drivev chains and a gearing including a frictionally controlled planetary gear device for each of said drive sprockets, and means to control said frictionallyc-ontrolled planetary geared reduction whereby an equal maximum amount of power may be given to both of said traction driving wheels, or a maximum amount of power may be transmitted to one traction wheel while a minimum amount of power is transmitted to said other traction wheel.

p Signed at Davenport, in the county of Polk and State of Florida, this 20th'day of December, A. D. 1926.

CHARLES E.. DAVIS.

22. In combination with a mining machine, I

iary pair of traction drivingwheels supported 

